Patent Document 1 (Japanese Laid-Open Patent No. 2004-27281), Patent Document 2 (Japanese Laid-Open Patent No. 2005-92375), and Patent Document 3 (Japanese Laid-Open Patent No. 7-21373) disclose embodiments of a personal authentication apparatus that irradiates infrared light or near infrared light on a finger to capture an image of a vein pattern within the finger and perform personal authentication based on the vein pattern.
Also, Patent Document 4 (Japanese Patent No. 3705766), Patent Document 5 (Japanese Laid-Open Patent No. 2001-61109), and Non-Patent Document 1 (Rui Shogenji et al., “Development of Thin Image Input Apparatus using Compound-Eye Optical System”, The Journal of the Institute of Image Information and Television Engineers, Vol. 57, No. 9, pp. 1135-1141, 2003) disclose embodiments of a thin image input apparatus that uses a compound-eye optical system. Further, Non-Patent Document 1 discloses an exemplary fingerprint inputting technique to be applied to a fingerprint authentication system.
The personal authentication apparatuses disclosed in Patent Documents 1, 2, and 3 use single-eye optical systems for inputting the vein pattern image so that restrictions are imposed with respect to the object distance and imaging distance and the apparatus may not be adequately miniaturized. It is noted that in order to enable installation of a personal authentication apparatus in an electronic apparatus such as a mobile phone, a miniature information terminal such as a PDA, or a laptop computer, the personal authentication apparatus has to be adequately miniaturized.
To miniaturize the personal authentication apparatus, the image input apparatus for inputting the image of an object within a living body such the veins of a finger or subdermal fingerprints has to be miniaturized as well. As is noted in Patent Documents 4 and 5, in miniaturizing the image input apparatus, it is generally advantageous to use a compound-eye optical system. However, in the case of using the image input apparatus for personal authentication, the image of the object within a living body to be input and used for personal authentication has to be captured with adequate image quality in addition to miniaturizing the image input apparatus.